I prototype using the flying bug method. Dead bug is where the dreaded ICs are placed label down on a piece of copper clad board. I leave the label up and spread the pins. It is held in place by the components that go to the foil ground plain. I have gone to five or six layers, but I have no trouble making modules and stacking those sideways from a master card.
Now once a module is working, it used to be a tape up to negative to PC Card.
Hopefully one does not bury unstable parts of the circuit
Now high parts count circuits are often multiple copies of the same circuitry with different values.
My biggest project was an STI meter the had multiple band pass filters each feeding multiple much lower frequency filters. Using 1% resistors and 2% capacitors avoided trimmers.
Now once a module is working, it used to be a tape up to negative to PC Card.
Hopefully one does not bury unstable parts of the circuit
Now high parts count circuits are often multiple copies of the same circuitry with different values.
My biggest project was an STI meter the had multiple band pass filters each feeding multiple much lower frequency filters. Using 1% resistors and 2% capacitors avoided trimmers.
Optimod Abuse
To put a fine point on it: all generations of the Optimod, but specifically the most recent ones I employ (8500 onward) have the best AGC action I have ever used in 30+ years of pro audio. When set up correctly it is almost unnoticeable. Why use it? DJ's are not known for their aplomb setting levels. The ones who actually try can only set it up at the beginning of a track, then go back to doing the rest of the DJ tasks like logging, queuing the next tracks, etc. In the meanwhile the song may have crescendoed by 10-20dB. This is one reason broadcast consoles have such high overload points; to allow for poor level setting and not clip, and let downstream limiters correct the mistake. The other reason is to use +8dBm as reference level to increase RFI immunity. In WXYC's signal path, the Orban Optimod is fed directly from a PR&E console which clips at +28dBm.
I belabor this point to state: WXYC's audio processing consist ONLY of the Orban's AGC, no hard limiting, no spectral compression, etc. WXYC uses only the one Optimod 8500, and the FM feed is taken directly from it as is the stream feed. Scott's statement that FM can sound good can be corroborated by your own ears if you care to listen to our HD stream at:
http://audio-mp3.ibiblio.org:8000/wxyc-alt.mp3
Sure, it is MP3, but at the max bitrate of 320kbps. Listening locally on a quality FM tuner in full quieting the quality is nearly indistinguishable from a CD other than a slightly increased noise floor.
Of course all of this is moot when a jock jacks their dumbphone into the board to play back lo-bitrate empty3 files...
To summarize: WXYC runs (basically) unprocessed 24/7; it can be and is done! The only reason a station would do this on off-peak hours is because they have to reduce the average level or risk hard-clipping by the transmitter as it protects it's FCC-mandated spectral mask. And it seems everybody in broadcasting has accepted that the listening public is so freakin stupid they only stop at the loudest sound on the dial. And yes, our average level is several dB lower than all of the processed stations including the local NPR affiliate.
Cheers!
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
1st on the internet
To put a fine point on it: all generations of the Optimod, but specifically the most recent ones I employ (8500 onward) have the best AGC action I have ever used in 30+ years of pro audio. When set up correctly it is almost unnoticeable. Why use it? DJ's are not known for their aplomb setting levels. The ones who actually try can only set it up at the beginning of a track, then go back to doing the rest of the DJ tasks like logging, queuing the next tracks, etc. In the meanwhile the song may have crescendoed by 10-20dB. This is one reason broadcast consoles have such high overload points; to allow for poor level setting and not clip, and let downstream limiters correct the mistake. The other reason is to use +8dBm as reference level to increase RFI immunity. In WXYC's signal path, the Orban Optimod is fed directly from a PR&E console which clips at +28dBm.
I belabor this point to state: WXYC's audio processing consist ONLY of the Orban's AGC, no hard limiting, no spectral compression, etc. WXYC uses only the one Optimod 8500, and the FM feed is taken directly from it as is the stream feed. Scott's statement that FM can sound good can be corroborated by your own ears if you care to listen to our HD stream at:
http://audio-mp3.ibiblio.org:8000/wxyc-alt.mp3
Sure, it is MP3, but at the max bitrate of 320kbps. Listening locally on a quality FM tuner in full quieting the quality is nearly indistinguishable from a CD other than a slightly increased noise floor.
Of course all of this is moot when a jock jacks their dumbphone into the board to play back lo-bitrate empty3 files...
To summarize: WXYC runs (basically) unprocessed 24/7; it can be and is done! The only reason a station would do this on off-peak hours is because they have to reduce the average level or risk hard-clipping by the transmitter as it protects it's FCC-mandated spectral mask. And it seems everybody in broadcasting has accepted that the listening public is so freakin stupid they only stop at the loudest sound on the dial. And yes, our average level is several dB lower than all of the processed stations including the local NPR affiliate.
Cheers!
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
1st on the internet
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> (probably a salesman more than anything, c.f. Noel Lee?)
I'm not sure he actually designed it (but surmise he did)
but Noel Lee at one time had a (tube) preamp that was
delightful .........
I'm not sure he actually designed it (but surmise he did)
but Noel Lee at one time had a (tube) preamp that was
delightful .........
You'll expand your musical horizons at the same time. All the internet connected TV's and little boxes have the entire FM streaming list for free(?), at least mine do. These days you don't need much of a connection to avoid drop-outs/re-buffering.
And most of us can't get close to that. I certainly can't. Bob and Jim were masters in that some of them were the size of a basket ball and not only worked but were an accurate analog representation of the chip under design. A skill that is being lost.
My comments on optimod misuse were all pointed at BBC radio 3. Every year around proms time the letters columns in HiFiNews were full of people pleading with the BBC to back off on the optimod for the proms. In their defense the BBC did always point out that they had to supply a service to people in cars and I am sure we have all had CDs that are unlistenable in car as you are forever riding gain.
I switched to listening on TV as soon as I had a NICAM TV as it was very depressing to hear orchestral crescendos having the life squeezed out of them. A 200 piece choir could come in and there would be no change in volume.
Oddly the BBC would change settings throughout the day, so late at night you would get some very good DR. The proms unfortunately were during 'drive time'.
Internet radio has been a boon!
I switched to listening on TV as soon as I had a NICAM TV as it was very depressing to hear orchestral crescendos having the life squeezed out of them. A 200 piece choir could come in and there would be no change in volume.
Oddly the BBC would change settings throughout the day, so late at night you would get some very good DR. The proms unfortunately were during 'drive time'.
Internet radio has been a boon!
Although modern simulation tools are incredibly powerful, making the lost skill of such prototyping a lot less significant. Even Pease, who hated them and expressed himself colorfully on the subject, used them a bit. He stopped designing chips after a while I believe.
Williams afaik did not design chips for Linear Tech, but was unsurpassed in applications. One client laments Williams' passing on a regular basis.
I do air circuits over a ground plane when I am in a terrible hurry, although also not for things destined for integration. Otherwise, following a good deal of thought and simulation, I use the Twin prototyping boards with ground plane one side and plated-through pad-per-hole, and sometimes with adapters when a given part is only available in SM. Connections requiring it, when the component leads are too short, are done with bus wire and teflon tubing, the latter to avoid meltback. I wonder how much PFOA is in my system?
No. Should have done in hindsight as prom 2 was a bit limp. will fire that up tomorrow night.
Hmmm, I suspect that we've all got it in us.....even for small prototypes, the seed of doom is in the choice of size and spacing of layout - all's well at first then we need to 'improve' it. And, after that a bit of cramming, the next step is to go multi-storey. Then we need to change part of the circuit which is crammed together on a low storey.........and in so doing we introduce one or more faults. Thus we have arrived at terminal complexity..........
It's not about the circuit, it's more about the human condition as applied to prototyping. Or is it just me ?
From 25+ years ago? No. Actually Hurricane Ivan 9/18/04 (18-9-04) wiped out just about everything I owned. So I don't even have my design file folder. Before everything was vulnerable to hacking we used to keep all the paper, negatives etc.
ES
Scott, I wish that were the case, that FM and for that AM were carried.
But they aren't and haven't been for a while. Are you talking Cable or
The U-nfortunate -Verse, non-compliments of AT&T.
We pay enough yet seems there is more advertizing than programming....
...and of course, the late night "paid program".
That said, sometimes we find good thing with little problem and
this I enjoy today as I start my day.
Diana Krall, Live from Rio
It just gets fun....
But they aren't and haven't been for a while. Are you talking Cable or
The U-nfortunate -Verse, non-compliments of AT&T.
We pay enough yet seems there is more advertizing than programming....
...and of course, the late night "paid program".
That said, sometimes we find good thing with little problem and
this I enjoy today as I start my day.
Diana Krall, Live from Rio
It just gets fun....
LOL Ray,
Rest assured they could. It's just that nobody else could.
It's kind of like musicians. You have those that read and
are at a loss without sheet music in front of them. And,
those that feel and play and wouldn't know what to do
with a piece of sheet music.
The ROKU works on any connection AFAIK they have an internet radio channel, or you can connect on your computer. Did you mean FM picked up by your cable company? Sorry I was talking about internet radio, some sound good (very good) like Howie's some less so.
The astronomer Rudolph Minkowski had a famously cluttered office, featuring stacks of papers on tables with no apparent lines of demarcation. According to the late Lawrence Aller, he also spoke in a barely comprehensible mumbling sort-of-growl. But if you asked him for a document, he would go to a given pile and pull it out.
I worked with someone who had similar piles of paper---but he couldn't find anything.
It's taken me years to get and stay organized as a matter of course. However the sheer volume of material doesn't fit in the local space and is in storage, mostly in banker's boxes, in file folders, and most of those boxes and folders are catalogued.
I can relate to that Brad. By all available accounts, my desk drawers are a holy mess, but ask me for something and 9 out of 10 times, I'll just reach in and get it for you. Been like that all my life.
The only thing I really never ever do is to try to work with a cluttered or worse tabletop. I need space to feel comfy. I need to have space for my ashtray, coffee mug, calculator (yep, still use one of those, a model from 1992, light powered TI-30, but I also still keep my dad's programmable HP from 1975 or so, red LED display, works perfectly).
The only thing I really never ever do is to try to work with a cluttered or worse tabletop. I need space to feel comfy. I need to have space for my ashtray, coffee mug, calculator (yep, still use one of those, a model from 1992, light powered TI-30, but I also still keep my dad's programmable HP from 1975 or so, red LED display, works perfectly).
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It seems that everything BUT audio design and cars is being discussed on this thread. I really wish that I could say more, but I am restricted to the conventional.
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